Compressor and method of lubrication

ABSTRACT

A Scotch yoke refrigeration compressor of the four cylinder Xtype has a rear discharge chamber containing a high pressure oil sump from which oil is led through a capillary tube to a cavity in the body containing a low pressure oil sump from which the oil is led to the parts to be lubricated. The pressure of oil in the low pressure sump is materially reduced but somewhat higher than the pressure in the areas of the lubricated parts. A high point of the low pressure sump is vented to a compressor inlet passage area having a pressure slightly below that in the low pressure sump and slightly above that in the areas of the lubricated parts.

United States Patent 1 3,695,786 Gannaway [4 1 Oct. 3, 1972 COMPRESSOR AND METHOD OF 3,208,667 9/1965 Boettcher ..4l8/85 LUBRICATION 3,312,387 4/1967 Cassidy ..4l8/88 7 l t 2] nven or Edwin L Gannaway, Sidney OhlO Primary Examiner wnham L. Freeh [73] Assrgnee: Copeland Refrigeration Corporation Attomey-Harness, Dickey & Pierce 22 Filed: Jan. 27, 1970 1 I [57] ABSTRACT [21] Appl. No.: 6,158 I A Scotch yoke refrigeration compressor of the four cylinder X-type has a rear discharge chamber contain- [52] US. Cl ..417/437, 184/6 i a hi h pressure oil sump from which oil is led [51] Ill. Cl ..F16n 13/00 through a capillary tube to a cavity in the body col-b [58] Fleld of Search, ..417/437, 521; mining a low pressure n Sump from which the oil is 418/854; 184/6 L led to the parts to be lubricated. The pressure of oil in the low pressure sump is materially reduced but [56] Reerences cued somewhat higher than the pressure in the areas of the UNITED STATES PATENTS lubricated parts. A high point of the low pressure sump 1s vented to a compressor inlet passage area hav- 3,563,675 2/ 1971 Strazmckas ..417/222 i a pressure Slightly below that in the low pressure 1,820,883 8/1931 Hueber ..417/555 sump and Slightly above that in the areas f the 2,020,678 11/1935 Estler ..l84/6 lubricated parw 2,513,547 7/1950 Buell et al ..417/571 2,551,623 5/ 1951 More ..l84/6 7 Claims, 28 Drawing Figures PATENTED HBT 3 I972 3 6 95. 7 8 6 sum 1 or 7 M! w W M? if 27 /4 INVENTOR.

' 44% m W FTZW/JKZ PATENTEDncTa m2 3.695.786

' SHEET l 0F 7 INVENTOR.

L -Eis- El I B f M PATENTEDucts I912 SHEET 6 0F 7 INVENTOR.

1 COMPRESSOR AND METHOD OF LUBRICATION BACKGROUND OF THE INVENTION The present invention is an improvement upon the lubrication systems disclosed in the copending applications of Edwin L. Gannaway and Robert M. Draper, Ser. No. 747,920 tiled July 26, 1968 and Ser. No. 767,030 filed Sept. 9, 1968, now US. Pat. No. 3,560,120, granted Feb. 2, 1971, and has as its overall objective the provision of an improved means and method for lubricating the components of'refrigeration compressors by a forced feed system powered entirely by discharge pressure, which effectively prevents flooding of the cylinders of the compressor with lubricant during off cycles, and which effectively separates the oil and refrigerant.

Other objects and advantages will be come apparent upon consideration of the present disclosure in its entirety.

BRIEF DESCRIPTION OF THE FIGURES OF DRAWING FIG. I is a central longitudinal sectional view, with parts in elevation, of a compressor incorporating the present invention;

FIG. 2 is a rear elevational view with parts broken away and in section;

FIG. '3 is a rear elevational view with the rear .cover removed and a screen assembly partly broken away;

FIG. 4 is a top plan view of the bottom head;

FIG. 5 is a bottom plan view of the bottom valve plate;

FIG. 6 is a bottom plan view of the top head;

FIG. 7 is a top plan view of the top valve plate;

FIG. 8 is a plan view of the inner face of one of the side heads;

FIG. 9 is a plan view of the outer face of one of the side valve'plates;

FIG. 10 is a front elevational view of the body;

FIG. 11 is a rear elevational view of the body, partly broken away;

FIG. 12 is a detailed sectional elevational view taken substantiallyon the line XII-XII of FIG. 11 and looking in the direction of the arrows;

FIG. 13 is a top plan view of the body;

FIG. 14 is a bottom plan view of the body;

FIG. 15 is a side elevational view of the body;

FIG. 16 is a central vertical sectional elevational view of the body;

FIG. 17 is a sectional elevational view taken substantially on the line XVIl--XVII of FIG. 11 and looking in the direction of the arrows, showing oneof the side heads in section;

FIG. 18 is a detailed sectional elevational view taken substantially on the line XVIII-XVIII of- FIG. 17 and looking in the direction of the arrows and FIGS. 19-28 inclusive are diagrammatic views corresponding generally to FIGS. 1, 3, 4, 5, 6, 7, 9, l3, l4 and 17 respectively, in which outlines of passages, chambers and ports are shown with coded hatchings designating relative pressure conditions.

DETAILED DESCRIPTION OF PREFERRED FORM OF THE INVENTION The principal moving parts of my preferred compressor construction are similar to those disclosed in the aforementioned patent application Ser. No. 747,920, and many of these will not require detailed description herein, the present invention being carried out mainly by altered arrangement and configuration of walls, ports passages and chambering of the block or body, heads, valve plates, covers, etc.

The cast aluminum block, 20, contains four cylinders, 21-24 inclusive, arranged at 90 to each other and perpendicular to the longitudinal axis of rotation of the crankshaft 25. The coaxial vertical pair of opposed cylinders 21,22 is offset rearwardly from the horizontal coaxial pair of opposed cylinders 23, 24. A rigid dual piston assembly is contained in each pair of cylinders, the pistons 26 of each pair being united by a centrally positionedScotch yoke 28 actuatable by a slide 30 driven by a throw 32 of the crankshaft.

The inlet process valve 33 delivers suction gas to an entrance chamber 34 in top head 35 .which communicates with the central low pressure crankcase area 36 centered in the block 20. Suction gas entering chamber 34 flows downwardly therefrom through passages 37, 38, 39 in the head 35, top valve plate 40, and block 20 respectively. The lower end of passage 39 opens forwardly into a chamber 41, the forwardportion of which is defined by the front bearing support plate 42. Chamber 41 opens rearwardly into the crankcase area 36 beneath the pistons, which are ported and provided with intake valves 44 on their head surfaces in known manner. Also in known manner, the valve plates for the individual cylinders are provided on their outer surfaces with exhaust valves 45. The bottom valve plate is designated 46 and the side valve plates are designated 48. The compressed gas is conducted from the outer ends of the cylinders via centrally positioned outlet chambers 49, 50 in the top and bottom heads, respectively, and 51 in the side heads 52. (The side-heads are alike) Chambers 49, 50, 51 communicate via cored passages in the block, identified by reference numbers 54-57 inclusive with a high pressure chamber generally designated 60 and formed partly of two sections, 61, 62 in the upper portion of the block and partly of sections 63, 64 located in top head 35 on either side of outlet chamber 49. The high pressure chamber 60 communicates via passages 58, 59 in the top valve'plate, and connected downflow passages 58, 59' cored in the rear wall of the block, with a combined discharge chamber and oil sump 65 of substantially annular form formed partly in the rear wall of the block and partly in the rear cover 66.

The front of the block has an opening 27 of large cross section which is closed and sealed by the front closure 42 and through which the crankshaft and all attached internal parts are installed with the exception of the pistons, which are installed through the open-outer ends of the cylinders and secured to the yokes by axial screws 29. The suction gas enters the compressor crankcase area through the front, as indicated.

The fact that the horizontal cylinders are positioned forwardly of the vertical cylinders and the rear I crankshaft parts are of lesser diameter permits the vertical high pressure passages 54, 55 and connecting horizontal passages 56, 57 for the outlet gas from the several cylinders, as well as drain holes 108, 109, to be accommodated in the block areas on either side of the wall bounding the bearing bore 85 and behind the horizontal cylinders.

The inner ends of the horizontal outlet gas passages 56, 57 intersect the risers 54, 55. The bottom ends of the risers 54, 55 and the outer ends of the connecting passages 56, 57 open at the bottom and side surfaces of the block for connection with the outlet head chambers 50 and 51 respectively through connecting openings 54, 55', 56', in the valve plates, to receive discharge gas from the bottom and side cylinders and conduct it to the high pressure chamber sections 61, 62 at the top of the block. The top head discharge chamber 49 has extension portions 49', 49 extending angularly laterally and forwardly to overlie sections 61, 62 providing free communication between discharge chamber 49 of the top cylinder and high pressure chamber 60 through openings 49, 49 in top valve plate 40. The wall 53 bounding the discharge chamber 49 and extensions 49', 49 therefore acts in compression to support and stiffen the head, and assists in isolating the suction downflow passage 37, but does not isolate from each other the chamber portions 49, 61, 62, 63, 64. Additional holes 97 are formed in the top valve plate to provide a larger cross sectional area of communication for flow of discharge gas from the lower three cylinders and the block sections 61, 62 of the first discharge chamber 60 to the head sections 63, 64, from which it is led via holes and passages 58,58, 59, 59 to the main discharge chamber 65.

Oil which collects in the bottom of chamber 65 is forced by the discharge pressure through a capillary tube 68 having a screened inlet end in the bottom sump portion of the chamber 65, thence through a drilled passage 70 into a relatively large low pressure oil sump chamber 72 formed partly in the bottom area of the block (in two sections, 72, 72 on either side) and partly in the bottom head 74, wherein the chambered section is designated 72 and extends around the front and sides of outlet chamber 50. Suitable openings 73, 73 in the bottom valve plate 46 coact in forming portions of the low pressure sump 72 by connecting the portions of the latter which are formed in the block and bottom head 74 respectively.

From opposite side comer portions near the bottom of the bottom head section 72 of sump chamber 72 out flow passages 75, 76 extend angularly upwardly and rearwardly to connect with channels 77, 78 in the top surface of bottom head 74 and which extend horizontally inwardly toward the vertical center plane of the compressor for communication with one of the riser passages 80, 81 which extend upwardly to communicate with an axial passage 82 which extends forwardly to communicate with a chamber 84 in the rear crankshaft bearing opening 85 formed in the rear wall of the block.

The disclosed compressor construction is particularly suitable for automotive air conditioning systems and is normally installed with the crankshaft positioned lengthwise of the vehicle. In order to insure that oil is taken from the low pointof the high pressure sump, the compressor may be installed slightly tilted toward the right or left, the riser 80 or 81 on the high side being blocked off by the gasket 83 between the valve plate 46 and bottom head, the gasket being orificed only in registry with the lower of the two feed passage systems 77-80 and 78-81.

The chamber 84 is formed partly by a hollowed out portion of a combined counterweight and rear male bearing portion 86 secured to the rear end of the crankshaft. The rear end of oil passage 88 in the crankshaft opens into chamber 84 to conduct oil therefrom to areas to be lubricated and which are fed from passage 88 via distribution ports as 90, 91. Port 91 delivers oil to the seal chamber 92, which is vented to inlet chamber 41 by a passage 93.

From the upper portions of the low pressure sump sections 72', 72 in each side of the block, riser passages 95, 96 extend upwardly and communicate through openings 98, 99 in the top valve plate 40 and connecting passages 100, 101, 102 in top head 35 with a passage 103 which extends forwardly through head 35 and opens into the inlet chamber 34 in alignment with the inlet opening thereinto from the process valve 33.

Oil which is pumped with the refrigerant through the compressor and which is discharged into the outlet chamber 65 is projected downwardly into the latter chamber through the passages 58', 59', while the gas must reverse its flow in order to pass upwardly through outlet passage 104 to the discharge valve 105. Due to such change of direction, the oil is effectively separated from the gas and retained in the sump space at the bottom of chamber 65. Oil which is separated in the high pressure chamber areas in the upper head and block portions drains from the latter to sump chamber 65 through drilled drain passages 108, 109 in the block. Agglomeration and separation of the oil from the gas is also assisted by a multiple screen assembly, generally designated 110 secured to the rear of the block and segregating the portion of chamber 65 in the block from the portion in the rear cover 66. The inlet screen 69 for the capillary tube 68 is located on the block side of the screen assembly 1 10. L:

In operation, when the compressor is driven by a suitable source of power (not shown) applied to the pulley portion 1 12 of the magnetic clutch assembly 1 14 which drives the crankshaft, oil in the high pressure sump space in chamber 65 is driven by outlet pressure through the capillary tube 68 to the low pressure oil sump 72. The capillary tube feeds oil at a desired rate to the low pressure oil sump 72. The pressure in sump 72 is slightly higher than that in the crankcase area 36. For example, if the discharge pressure in chamber 65 is of the order of 250 psi, the pressure in sump 72 might be 40 psi, while crankcase pressure might be of the order of 38 psi. The pressure at the mouth of passage 103 in inlet chamber 34 will be slightly below the pressure in chamber 72, but slightly above crankcase pressure. Thus the sump 72 is actually at an intermediate pressure. In the preferred construction shown, the ramming effect of the inflowing gas which is directed against the mouth of passage 103 assists in maintaining the pressure at the chamber end of the passage 103 slightly higher than the pressure in the crankcase area, yet low enough so that gas which separates from the refrigerant in sump 72 and which has entered the latter with the oil is vented via passage 103 to the intake.

Normally only gas passes to the intake via passage 103. A slight pressure drop of course also occurs in the I passages 37, 41, etc., leading to the crankcase area 36 which contains the parts to be lubricated, so that the pressure differential between sump 72 and the crankcase area is sufficient to insure positive lubrication. Thus failure of lubrication due to refrigerant vapor in the oil passages and flooding of the cylinders with oil during off cycles of the compressor, are effectively prevented. The capacity of the sump 72 is sufficient to accommodate the full quantity of lubricant, and the pressure in sump 72 and in the crankcase space immediately equalizes when the compressor stops.

This Detailed Description of Preferred Form of the Invention, and the accompanying drawings, have been furnished in compliance with the statutory requirement to set forth the best mode contemplated by the inventor of carrying out the invention. The prior portions consisting of the Abstract of the Disclosure and the Background of the Invention are furnished without prejudice in an effort to comply with administrative requirements of the Patent Ofiice.

What is claimed is:

1. A refrigeration compressor having an inlet area, a discharge chamber, a low pressure region containing parts to be lubricated, a high pressure oil sump pressurized by said discharge chamber, a second chamber defining a low pressure oil sump, pressure reducing oilconducting means connecting said high pressure oil sump to said second chamber and tending to maintain said second chamber at a pressure somewhat above that in said low pressure region but substantially below that in high pressure sump, and conduit portions connecting a lower portion of said low pressure oil sump to said parts to be lubricated, the capacity of the low pressure oil sump being sufficient to accommodate the entire oil supply of the compressor.

2. A compressor as defined in claim 1 wherein said low pressure region is at a pressure somewhat below that in said inlet area when the compressor is running, and vent means connecting said second chamber to said inlet area.

3. A compressor as defined in claim 2 including a body having said second chamber in a lower portion thereof and said last mentioned low pressure area in an upper portion thereof 4. In a compressor as defined in claim 2, a body having said low pressure oil sump chamber located near the bottom and said low pressure area in an upper portion thereof.

5. A refrigeration compressor as defined in claim 2 including a body, a crankshaft joumaled therein and drivable from one end, a plurality of radial cylinders perpendicular to the axis of the crankshaft, said discharge chamber and high pressure oil sump being combined in a single chamber located at a part of the body appurtenant to the other end of the crankshaft, the second chamber being located in a lower portion of the body, said means connecting the low pressure oil sump to the parts to be lubricated being connected to a bottom area of said second chamber and leading to an end of said crankshaft opposite the drivable end, and said vent means being connected to an upper area of saids ond chamber.

6. he method of lubricating a refrigeration compressor having a low pressure suction area containing parts to be lubricated, a high pressure discharge area, and a charge of lubricant, which comprises collecting lubricant form the compressor discharge in a high pressure sump and pressurizing it by pressure from the discharge area, conducting lubricant from said high pressure sump to an intermediate pressure sump having a capacity sufficient to accommodate the entire charge, while reducing its pressure to a value lower than that in the discharge area but higher than that in said suction area, and conducting lubricant from said intermediate pressure sump to the parts to be lubricated.

7. A method as defined in claim 6 for use with a com pressor having an inlet area wherein the operating pressure is below that in the intermediate pressure sump but above that in said suction area, and wherein gas is liberated from the lubricant in the intermediate pressure sump, comprising the further step of conducting gas from an upper portion of the intermediate pressure sump to said inlet area.

JUNH'EED STATES PATENT- eFmcE 1 5 QERTIFMIATE OF CORRECTEON Patent No. 3, 695, 786 Dated October 3, 1972 Inventor (s) Edwin L Gannaway It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the heading of Sheet 1 of the drawing, change "Sheet 1 of 7" to read --Sheet 1 of 11--.

On the heading of Sheet 2 of the drawing, change "Sheet 2 of 7" to read Sheet 2 of 11.

On the heading of Sheet 3 of the drawing, change "Sheet 3 of 7" to read Sheet 3 of 11-.

On the heading of Sheet 4 of the drawing, change "Sheet 4 of 7" to read -Shect 4 of ll--.

On the heading of Sheet 5 of the drawing, change "Sheet 5 of 7 to read --Sheet 5 of 11-.

On'the heading of Sheet 6 of the drawing, change "Sheet 6 of 7" to read Sheet 6 of 11-.

On the heading of Sheet 7- of the drawing, change "Sheet 7 of 7" to read --Sheet 7 of 11--.

Add sheets 8 toll inclusive of the drawing, as attached hereto.

Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

McCOY M, GIBSON JR. C, MaRSI IALL DANN Attesting Officer Commissioner of Patents FORM PO-1050 (10-69) USCOMM DC fl0376-P69 1L5, GOVSRHMENT PRINTING OFFICE ll! O3G-38l 

1. A refrigeration compressor having an inlet area, a discharge chamber, a low pressure region containing parts to be lubricated, a high pressure oil sump pressurized by said discharge chamber, a second chamber defining a low pressure oil sump, pressure reducing oil-conducting means connecting said high pressure oil sump to said second chamber and tending to maintain said second chamber at a pressure somewhat above that in said low pressure region but substantially below that in high pressure sump, and conduit portions connecting a lower portion of said low pressure oil sump to said parts To be lubricated, the capacity of the low pressure oil sump being sufficient to accommodate the entire oil supply of the compressor.
 2. A compressor as defined in claim 1 wherein said low pressure region is at a pressure somewhat below that in said inlet area when the compressor is running, and vent means connecting said second chamber to said inlet area.
 3. A compressor as defined in claim 2 including a body having said second chamber in a lower portion thereof and said last mentioned low pressure area in an upper portion thereof
 4. In a compressor as defined in claim 2, a body having said low pressure oil sump chamber located near the bottom and said low pressure area in an upper portion thereof.
 5. A refrigeration compressor as defined in claim 2 including a body, a crankshaft journaled therein and drivable from one end, a plurality of radial cylinders perpendicular to the axis of the crankshaft, said discharge chamber and high pressure oil sump being combined in a single chamber located at a part of the body appurtenant to the other end of the crankshaft, the second chamber being located in a lower portion of the body, said means connecting the low pressure oil sump to the parts to be lubricated being connected to a bottom area of said second chamber and leading to an end of said crankshaft opposite the drivable end, and said vent means being connected to an upper area of said second chamber.
 6. The method of lubricating a refrigeration compressor having a low pressure suction area containing parts to be lubricated, a high pressure discharge area, and a charge of lubricant, which comprises collecting lubricant form the compressor discharge in a high pressure sump and pressurizing it by pressure from the discharge area, conducting lubricant from said high pressure sump to an intermediate pressure sump having a capacity sufficient to accommodate the entire charge, while reducing its pressure to a value lower than that in the discharge area but higher than that in said suction area, and conducting lubricant from said intermediate pressure sump to the parts to be lubricated.
 7. A method as defined in claim 6 for use with a compressor having an inlet area wherein the operating pressure is below that in the intermediate pressure sump but above that in said suction area, and wherein gas is liberated from the lubricant in the intermediate pressure sump, comprising the further step of conducting gas from an upper portion of the intermediate pressure sump to said inlet area. 